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MapReduce >> mail # user >> client side I/O buffering

Lukas Kairies 2013-08-27, 14:58
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Re: client side I/O buffering
Hi Lukas,

HDFS read-ahead/write caching is provided by DFSInputStream and
DFSOutputStream respectively (see CachingStrategy).

Other file system providers need to implement their own caching strategy.
FileSystem#open and FileContext#open just return a seekable input stream
with no read-ahead assumptions.

On Tue, Aug 27, 2013 at 7:58 AM, Lukas Kairies <

> Hello,
> I know that the client caches write requests before they send to a
> datanode and that the client uses read-ahead, but where exactly is this
> implemented, Hadoop or HDFS? Or better question, will write cache and
> read-ahead also available when Hadoop uses another filesysten than HDFS?
> Thanks,
> Lukas K.

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